Method of installing breakwater caissons

ABSTRACT

This disclosure is directed to caissons and to a method of constructing seawalls, breakwaters, jetties, groins and the like utilizing the caissons which are closed sided, hollow, bottomless and compartmented precast concrete structures adapted to be air pressurized for flotation in water with their bottomless sides downward to the erection site and then depressurized and sunk into position and anchored against movement by imbedding in the water bottom and by filling with dredged and/or pumped in solids.

United States Patent La Peyre 1 Feb. 8, 1972 [54] METHOD OF INSTALLING BREAKWATER CAISSONS [72] Inventor: James H. La Peyre, 13 Richmond PL, New

Orleans, La.

[22] Filed: Oct. 16, 1969 [21] Appl.No.: 866,823

[52] US. Cl ..6l/5, 61/46 [51] Int. I 021) 3/06 [58] Field ofSearch ..6l/2, 3, 4, 5, 46, 46.5, 81, 61/82 [56] References Cited UNITED STATES PATENTS 1,310,461 7/1919 Williams .61/4 X 1,399,286 12/1921 Baer 3,276,209 10/1966 Mosdell ..6l/5

3,490,239 1/1970 Vincent ..6 1/4 FOREIGN PATENTS OR APPLICATIONS 1,373,090 8/1964 France ..61/5

Primary Examiner-David J. Williamowsky Assistant Examiner-David H. Corbin Att0meyWilkinson, Mawhinney & Theibault [57] ABSTRACT This disclosure is directed to caissons and to a method of constructing seawalls, breakwaters, jetties, groins and the like utilizing the caissons which are closed sided, hollow, bottomless and compartmented precast concrete structures adapted to be air pressurized for flotationin water with their bottomless sides downward to the erection site and then depressurized and sunk into position and anchored against movement by imbedding in the water bottom and by filling with dredged and/or pumped in solids.

2 Claims, 15 Drawing Figures PATENTEDFEB 81912 3,540,075

SHEET 1 BF -3 INVENTOR. JAMES M. LAPEYRE H6. 1 @MMQ m ATTOR/VZ' PATENTED FEB 81972 FIG. .3 l!

SHEET 2- 0F 3 I l l I Y l I l 1 1 I I l l INVEN TOR JAMES M LAPEYRE PATENTEDFEB 81972 131640.075

SHEET 3 [1F 3 INVENTOR.

JAMES M. LAPEYER ATT NEYS- METHOD OF INSTALLING BREAKWATER CAISSONS This invention relates generally to the construction of seawalls, breakwaters, jetties, groins and the like, and specifically to a method of constructing such structures using precast reinforced concrete caissons which may be floated to the erection site and sunk into place by controlling air pressure and volume within the caisson before and/or during transport and placement at the erection site.

Conventional breakwaters, jetties and groins are constructed in a variety of ways, including timber sheet pile construction, rubble mound construction, circular steel cylinders which are rubble and sand filled, and concrete caissons which have closed bottoms and open tops, and which are floated to the site then filled with sand or rubble then capped at their tops with poured or precast concrete at the erection site. In addition to requiring laborious top capping at the site, conventional floatable concrete caisson construction requires extensive underwater foundation preparation in order to provide a proper support for the bottoms of the concrete caissons otherwise the caissons would eventually topple due to erosion and horizontal forces transmitted to the foundation by water and wave actron.

In contradistinction, the present invention teaches of prefabricated reinforced concrete caissons which have no bottoms but which are otherwise closed, except for suitable air and dredge filling ports at or near the tops, and which have sloping sidewalls that support the caisson against vertical as well as horizontal movement once installation is completed.

Such caissons permit a novel method of breakwater construction since the complete breakwater may be prefabricated in segments requiring no further exterior finishing, and which may be floated and installed at a remote construction site.

Once the caisson is in place at the erection site it may be filled with dredged ocean bottom or other solid material by pumping in same along with water which is bled off as the solids settle.

Accordingly it is an object of this invention to provide a moreeconomical method for the erection of concrete breakwaters, jetties and groins etc., by using prefabricated and prefinished bottomless concrete caissons, which are floated bottomless side downwardly to the erection site.

Another object of the present invention is the provision of a more rapid construction method for building breakwaters, jetties and groins.

A further object of the present invention is the provision of a method of breakwater, jetty and groin construction which incorporates a bottomless caisson requiring minimal or no underwater foundation preparation at the erection site prior to the arrival and placement of the caisson.

A further object of the present invention is the provision of a method of breakwater, jetty or groin construction which is not readily subject to wave damage during the construction period since the caissons may be protected from wind and wave action simply by reducing air pressure within the caissons thereby lowering the caissons in the water to reduce movement of the caissons for the duration of the wave and wind activity.

A still further object of the present invention is the provision of a method of constructing breakwaters, jetties and groins which utilize to the fullest available mechanical equipment such as tugboat's, high capacity low-pressure air compressors and dredges, and minimizes the need for manual labor at the erection site.

A further object of the present invention is the provision of a precast concrete caisson having sloping sidewalls so as to provide upon installation of the caisson a prefabricated structure which is, because of the sloping walls, highly resistant to vertical as well as horizontal movement.

A further object of the present invention is the provision of a precast concrete caisson having sloping sidewalls which may be terraced in steps so that once installed no further steps or ladders need be provided for persons requiring same.

A further object of the present invention is the provision of a bottomless, hollow elongated caisson having end walls which are V-shaped in plan so as to permit streamlining and nesting during transportation and interlocking upon installation so as to inhibit wave wash between abutting caissons.

With the foregoing and other objects in view, the invention will be more fully described hereinafter, and will be more particularly pointed out in the claims appended hereto.

In the drawings wherein like symbols refer to like or corresponding parts throughout the several views.

FIG. 1 is a transverse section taken through a caisson according to the present invention being floated to a location site.

FIG. 2 is a view similar to FIG. 1 showing the caisson raised by air pressure prior to seating in place.

FIG. 3 is a transverse section of a breakwater installation in accordance with the present invention.

FIG. 4 is a transverse section taken through a modified form of caisson being floated to an installation site under pressure.

FIG. 5 is a transverse section of the caisson of FIG. 4 in its seated and filled condition.

FIGS. 6 and 7 are views similar to FIGS. 4 and 5 showing the floating into position and anchoring by introduction of a flowable anchoring medium.

FIG. 8 is a plan view of a breakwater caisson showing in dotted lines a transverse partition with pressurized air supply means to each side of the partition.

FIG. 9 is a side elevational view showing in dotted lines the transverse partition forming fore and aft partitions.

FIG. 10 is a plan view of a breakwater caisson showing in dotted lines both transverse and longitudinal partitions forming four separate compartments each equipped with its own pressurized air supply means.

FIG. 11 is a side elevational view shown in dotted lines the transverse and longitudinal partitions.

FIG. 12 is a caisson having a V-shaped end and a rounded end intended as the terminating end caisson in a plurality of caissons forming a breakwater.

FIG. 13 is a similar view showing a caisson suited to terminate the opposite end of a finished breakwater.

FIG. 14 is a top plan view of two caissons of the present invention being pushed to an installation site by a tugboat.

FIG. 15 is a perspective view of a breakwater caisson constructed in accordance with the present invention being pushed to an installation site by tugboat.

Referring to FIGS. 1 8L 2, 10 designates a hollow, elongated caisson having an open bottom 11, vertical sidewalls 12 and 13, longitudinal partition 12A, a truncated roof or top 16, having sloping sides 17 and 18. Located at or near the top is a pipe or other suitable port 19, through which low-pressure air from a blower 20 or other air source is supplied.

The caisson is precast of concrete and placed into the water 21 with its bottomless side 11 downwardly. By regulating the pressure within the caisson 10 its degree of flotation is controlled so as to insure its stability and regulate its draft during transport to the erection site. When on location at the erection site, air within the caisson is vented off and the caisson is allowed to sink so that its vertical sides 12, 13, 14 and 15 settle into the ocean bottom under the weight of the caisson.

Since the caisson is bottomless, the walls 12, 13, 15, 14, 12A and 14A have exposed bottom end surfaces 13A which have exceedingly small areas as compared with the area covered by the entire caisson. This small end surface area of the walls coupled with the great weight of the caisson permits the caisson to be readily lowered and sunk into the ocean or beach bottom to a depth which will insure against horizontal movement of the installed structure. If the ocean bottom is too soft to support the caisson during filling and after the vertical walls have penetrated the bottom to the desired depth, further settling is prevented by maintaining pressurized air within the caisson. The caisson is then filled by pumping in dredged material through a suitable inlet port such as 24 shown in FIG. 7. While the dredged material such as mud and/or sand is pumped in with dredge water and settles within the caisson, the remaining pressurized air space within the caisson is reduced as water fills the caisson so that the structure is under temporary hydraulic support. During the filling operation, the dredged solid material settles while the water is permitted to escape through the adjustable standpipe 25 as seen in FIG. 7. The height of a standpipe 25 may be adjusted to control the hydraulic pressure within the caisson thereby supporting same until sufficient fill is in place within the caisson and against the sloping sidewalls to support the structure. When eventually the caisson is sufficiently filled with solid material the various air and hydraulic ports are closed with concrete or other material.

Since. the caisson, once installed, completely protects the entrapped fill material against water and wave action, the fill material may be of fine particles such as sand, mud and clay. These materials are usually readily available at the construction site and at a cost far less than that of large boulders or other rubble. Once filled the caisson is then supported against vertical movement downwardly since the internal sloping sides of the caisson resist vertical as well as horizontal movement. When the caisson is filled, the fill material becomes the vertical foundation as well as a massive horizontal anchor.

In cases where the caisson is used in construction of a sea wall as shown in FIG. 3, the back fill 22 is dredged up from the seaward side of the caisson and deposited on the land side thereby creating new land area at the desired degree of elevatron.

FIGS. 4 through 7 show a modified form of caisson similar to FIGS. 1 through 3 but constructed so that the sloping sidewalls l7 and 18 are terraced in steps as indicated by 23. This increases the impact strength of the structure and simultaneously provides a walkway ladder for bathers and seamen etc.

FIGS. 8 and 9 show a caisson which is divided into fore and aft compartments by transverse partition 14A. By dividing the caisson into two separate compartments it becomes possible to separately control the air pressure within each of the compartments. This feature facilitates not only the leveling of the caisson during transport but also speeds the installation of the caisson, since it permits the caisson to be agitated or rocked about a lateral axis while it is lowered into the ocean bottom to its proper depth. The rocking or agitating of the caisson, which is simply accomplished by alternately increasing and decreasing the compartment pressures within the caissons, causes the wall ends to pump their way into the sea bottom. Repositioning and removal of a misplaced caisson is made possible by reintroducing air under pressure into the caisson.

Simply by controlling air pressures it is possible to easily control with a high degree of accuracy the final position and level of the caisson. It is even possible to move large caissons, bottoms down, over solid surfaces if the volume of flow or pressurized air is sufficient. This capability facilitates placement of the Y caissons in very shallow water or upon a dry shore. Likewise it may be used to assist in launching of the caissons at the concrete factory should this be required.

FIGS. 10 and 11 show a caisson which is divided into four compartments by longitudinal partition 12A and transverse partition MA. This permits controlled pitching about the longitudinal axis as well as the lateral axis since, air pressure can be independently controlled in each of the four compartments. This ability of the caisson to be rocked in any direction facilitates its installation in water bottoms where a combination of rocking directions is required.

FIGS. 12 and 13 simply indicate caissons which are intended as the terminating caisson in a string or series of caissons which make up a breakwater. Instead of having the rounded end A, it may be desirable for some breakwaters to have square ends such as in cases where it is desirable to dock boats at the end of a breakwater.

As best seen in FIGS. 14 and 15 the caissons 10 are pushed by a tug 26 which also provides electricity and control to the blowers through cables 27 connected to the tugs electrical system.

In lieu of blowers 20, air may be supplied to the caissons via air conduits or pipes which derive their source of compressed air from compressors on the boat.

In cases where water transport conditions and water depths are known in advance, and control of buoyancy is not necessary during transport it is possible to pressurize the caissons prior to transport, with a predetermined quantity of air which remains captured within the caisson for the duration of the transport voyage. In such cases it is necessary that at least that portion of the interior of the caisson which is under air pressure be leak proof in order to prevent escapement of the air through cracks or pores in the concrete during transit. In cases where air may be continuously or intermittently fed into the caisson during transit, it is not absolutely necessary to have a leak proof caisson, since loss of air may be made up during transit.

As best seen in FIG. 15, the caisson may be constructed with an integral strengthening weblike pier or buttress 28 which is desirable in some breakwaters, to facilitate boat mooring and to define a vertical post against which boats may be moored at various tide levels. Such buttresses may be incorporated at any desired interval along the length of the caisson and may be equipped with suitable rubber bumpers and mooring cleats which are not shown in the drawings.

It should be clear from the foregoing that the caisson units may be manufactured in any convenient length and width and may be assembled and installed in any suitable number to define breakwaters of any length and which are neat and uniform in appearance and which are also highly functional and maintenance free.

For the purpose of clarity the word breakwater as used in the claims shall be interpreted to mean any structure permanently erected in or near the water to control or interrupt movement of the water or to afford protection of harbors, roadways and shorelines against water action.

Whatl claim is:

1. The method of establishing a breakwater comprising a. prefabricating a rectangular boxlike bottomless caisson having sidewalls at least a portion of which are sloping and at least a longitudinal partition,

b. placing the bottomless caisson in the water with its open bottom directed downwardly,

c. floating the caisson on pressurized air captured within the top of the caisson while maintaining the air pressure at a pressure level sufficient to maintain the caisson at the desired flotation level for transport to the breakwater site,

d. transporting the floating caisson to the breakwater erection site,

e. reducing the air pressure within the caisson sequentially on each side of the partition causing rocking movement of the caisson about its longitudinal axis to seat the caisson at the breakwater site,

f. anchoring the caisson by at least partially filling the compartments of the caisson with flowable materials at least a portion of which are solids.

2. The method of establishing a breakwater comprising a. prefabricating a plurality of rectangular boxlike bottomless caissons having sidewalls at least a portion of which are sloping and at least a longitudinal and a transverse partition,

b. placing the bottomless caissons in the water with their open bottoms directed downwardly,

c. floating the caissons on pressurized air captured within the top of the caissons while maintaining the air pressure at a pressure level sufficient to maintain the caissons at the desired flotation level for transport to the breakwater site,

d. transporting the floating caissons to the breakwater erection site,

e. reducing the air pressure within the caissons sequentially on each side of the longitudinal partition causing rocking movement of the caissons about their longitudinal axes and on each side of the transverse partition causing rocking movement of the caissons about their transverse axes to align a series of abutting caissons in a substantially level breakwater and to seat the caissons at the breakwater site, f. anchoring the caissons by at least partially filling the compartments of the caissons with flowable materials at least 5 a portion of which are solids.

v Inventor(s) UNITED: STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. O75 Dated February 8, 1972 JAMES M. LAPEYRE It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

The name of the inventor, appearing in the heading of the patent, is misspelled. The correct spelling should JAMES M. LAPEYRE Signed and sealed this 20th day of Jane 1972.

(SEAL) Attest:

ROBERT GOTT SGHALK EDWARD M.FLETCHER, JR.

Attesting Officer Commissioner of Patents USCOMM-DC 60376-P69 #1 us. GOVERNMENT PRINTING OFFICE I969 0-366-334 '\ORM F'O-IOSO (10-69) 

1. The method of establishing a breakwater comprising a. prefabricating a rectangular boxlike bottomless caisson having sidewalls at least a portion of which are sloping and at least a longitudinal partition, b. placing the bottomless caisson in the water with its open bottom directed downwardly, c. floating the caisson on pressurized air captured within the top of the caisson while maintaining the air Pressure at a pressure level sufficient to maintain the caisson at the desired flotation level for transport to the breakwater site, d. transporting the floating caisson to the breakwater erection site, e. reducing the air pressure within the caisson sequentially on each side of the partition causing rocking movement of the caisson about its longitudinal axis to seat the caisson at the breakwater site, f. anchoring the caisson by at least partially filling the compartments of the caisson with flowable materials at least a portion of which are solids.
 2. The method of establishing a breakwater comprising a. prefabricating a plurality of rectangular boxlike bottomless caissons having sidewalls at least a portion of which are sloping and at least a longitudinal and a transverse partition, b. placing the bottomless caissons in the water with their open bottoms directed downwardly, c. floating the caissons on pressurized air captured within the top of the caissons while maintaining the air pressure at a pressure level sufficient to maintain the caissons at the desired flotation level for transport to the breakwater site, d. transporting the floating caissons to the breakwater erection site, e. reducing the air pressure within the caissons sequentially on each side of the longitudinal partition causing rocking movement of the caissons about their longitudinal axes and on each side of the transverse partition causing rocking movement of the caissons about their transverse axes to align a series of abutting caissons in a substantially level breakwater and to seat the caissons at the breakwater site, f. anchoring the caissons by at least partially filling the compartments of the caissons with flowable materials at least a portion of which are solids. 